Prime Number: Which number greater than 1 has exactly two distinct positive factors, 1 and itself?

Prime Number: Which number greater than 1 has exactly two distinct positive factors, 1 and itself?

• A. Composite Number
• B. Prime Number
• C. Even Number
• D. Whole Number

Answer: (B)

The fundamental idea here is a prime number: a number greater than 1 that has exactly two distinct positive factors, 1 and itself. This means numbers that have any other factors are not prime. For example, 5 has exactly the factors 1 and 5, so it’s prime; 6 has factors 1, 2, 3, and 6, so it’s not prime. Numbers that are even aren’t automatically prime; 2 is the only even prime, but most even numbers have more than two factors. Whole numbers include 0 and 1, and neither of those have exactly two distinct positive factors. So the description points to a prime number.

The fundamental idea here is a prime number: a number greater than 1 that has exactly two distinct positive factors, 1 and itself. This means numbers that have any other factors are not prime. For example, 5 has exactly the factors 1 and 5, so it’s prime; 6 has factors 1, 2, 3, and 6, so it’s not prime. Numbers that are even aren’t automatically prime; 2 is the only even prime, but most even numbers have more than two factors. Whole numbers include 0 and 1, and neither of those have exactly two distinct positive factors. So the description points to a prime number.